Functional Study of Heat Shock Factor Binding Protein in Arabidopsis thaliana
Date Issued
2010
Date
2010
Author(s)
Hsu, Shih-Feng
Abstract
Heat shock response (HSR) is a universal mechanism in all organisms. It is under tight regulation by heat shock factors (HSFs) and heat shock proteins (HSPs) after heat shock (HS) to prevent stress damage. On the attenuation of HSR, HSP70 and HSF binding protein 1 (HSBP1) interact with HSF1 and thus dissociate trimeric HSF1 into an inert monomeric form in humans. However, little is known about the effect of HSBP with thermal stress in plants. This report describes our investigation of the role of AtHSBP in Arabidopsis by genetic and molecular approaches. AtHSBP was heat-inducible and ubiquitously expressed in all tissues; AtHSBP was also crucial for seed development after fertilization and during embryogenesis, as demonstrated by AtHSBP-knockout lines showing seed abortion. Thermotolerance results showed that AtHSBP participates in acquired thermotolerance but not basal thermotolerance and is a negative regulator of HSR. Subcellular localization revealed that the cytosolic-localized AtHSBP translocated to the nucleus in response to HS. Protoplast two-hybrid assay results confirmed that AtHSBP interacts with itself and with the HSFs, AtHSFA1a, AtHSFA1b, and AtHSFA2. The mutagenesis assay shows that the conserved residues of the hydrophobic heptad repeat domains in AtHSBP are important for retaining AtHSBP in the cytoplasm under normal growth conditions and for interacting with AtHSFs. AtHSBP also negatively affected AtHSFA1b DNA-binding capacity in vitro. Quantitative PCR and western blot analysis demonstrated that altered levels of AtHSBP lead to differential HSP expression mainly during the recovery from HS. These studies provide a new insight into HSBP in plants and reveal that AtHSBP is a negative regulator of HSR and required for seed development.
Subjects
heat shock
heat shock response
heat shock protein
heat shock facotr
heat shock factor binding protein
HSBP
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-F91226006-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):c0aa0f9500888347ab6e7872daae9b8a